Comparison of Three Consciousness Assessment Scales in Poisoned Patients and Recommendation of a New Scale: AVPU Plus

Background: Few methods have been introduced to assess the level of consciousness in critically-ill patients. This study was designed to evaluate how the AlertVerbalPainfulUnresponsive (AVPU) responsive scale corresponds with the Glasgow Coma Scale (GCS) and Richmond Agitation-Sedation Scale (RASS) scores in drug-poisoned patients and to devise an augmented AVPU scale. Methods: In this prospective study, patients with diagnosis of acute drug poisoning were included and their level of consciousness was assessed using GCS, RASS and AVPU scales. Results: Overall, 165 poisoned patients (59% female) were studied. According to AVPU scale, 123 patients (74.5%) were graded as “alert”, 26 patients (15.8%) as “responsive to verbal stimulation”, 10 patients (6.1%) as “responsive to painful stimulation”, and 6 patients as “unresponsive” (3.6%). AVPU grades of "alert", "responsive to verbal stimulation", "responsive to painful stimulation" and "unresponsive" corresponded with median [IQR] GCS scores of 15 [15–15], 13 [12–13], 8 [7–10] and 6 [5–6], and median [IQR] RASS scores of -1 [-1 – +1], -2 [-3 – -1], -3 [-4 – -1], -5 [-5 – -5], respectively. By taking the median of RASS scores corresponding with each AVPU grade, an augmented AVPU scale for the assessment of consciousness was devised. The first proposed version of AVPU plus includes 14 qualitative grades of consciousness. By application of this scale, clinicians can evaluate both the alertness/attentiveness and arousal/excitability of poisoned and critical patients. Conclusion: The AVPU plus is a new scale designed for more detailed assessment of neurologic status of poisoned and critical patients. The prognostic-ability, reliability and validity of the scale should be investigated in future studies.